Tread patterns in which a plurality of sipes is disposed in a tire pattern in order to enhance braking performance on ice of studless tires are known. Also, in recent years, there is a tendency toward increasing the number of sipes. However, sipe density is increased as a result of increasing the number of sipes, and while this leads to an increase in the number of edges, it also leads to the problems of the overall rigidity of the block declining and braking performance on ice declining. Therefore, technology has been proposed in which collapse of the portions of a block that are sandwiched by sipes is minimized and the decline of block rigidity is reduced by disposing recesses and protrusions within the sipes (Japanese Patent No. 3180160).
On the other hand, focusing on steering stability on dry road surfaces and traction performance on snowy and icy road surfaces and wet road surfaces, with only recesses and protrusions within the sipes, it is not possible to increase the traction performance on snowy and icy road surfaces and wet road surfaces while maintaining steering stability on dry road surfaces.